1. Field of the Invention
The present invention relates to a shock absorber control system, particularly to a shock absorber control system which determines bad road conditions in accordance with a speed signal from a vehicle speed sensor and regulates the attenuation forces of the shock absorbers in response to the road conditions and a method of controlling the same.
2. Description of the Prior Art
Recently, highways and roads for motor vehicles are being highly equipped. However, there still remain unpaved roads such as gravel roads and dirt roads and how to maintain stable steering and running of vehicles on these bad roads has become a major problem.
Namely, when running on a bad road, vehicle handling becomes uncontrollable w,ich directly results not only from the road conditions, but also from the difficulty due to bounding and rebounding forward and backward, and right and left as well as rolling of the vehicle body.
Now, the inventor has found that the following differences occur when driving a vehicle both on good roads and bad roads. That is, as shown in FIG. 1, when running on a good road at a predetermined constant vehicle speed, the waveforms of the output signal from a vehicle speed sensor become the ones as shown in FIG. 1(A) with each period T1, T2, T3, T4 . . . of the output signal being equal with each other, while when running on a bad road at the same predetermined constant vehicle speed, the waveforms of the output signal from the same vehicle speed sensor become the ones as shown in FIG. 1(B) with each time period or duration T1', T2', T3', T4' . . . being different from each other.